Field of Invention
The present disclosure relates to an image sensor, and more particularly, to a structure and method for reducing optical crosstalk in an image sensor.
Description of Related Art
In semiconductor technology, an image sensor is used for sensing a volume of exposed light projected towards it to form an image. For converting various photo energy of the light into electrical signals, the image sensor of a semiconductor provides a grid of pixels which may contain photosensitive diodes, reset transistors, source follower transistors, pinned layer photodiodes, and/or transfer transistors. Common types of the pixel grids include a complementary metal-oxide-semiconductor (CMOS) image sensor (CIS), an active-pixel sensor (APS), a passive-pixel sensor and a charged-coupled device (CCD) sensor. These sensors are widely used in various applications such as digital still camera or mobile phone camera devices.
However, the grid of pixels of the image sensors may suffer from crosstalk while incident light targeted for one pixel grid of an image sensor element traverses other neighboring image sensor elements. As a result, a blaze of light having an overflow of electrons may occur due to the undesired light that spread across other the adjacent image sensor elements, so as to reduce overall optical sensitivity and result in poor color separation. Accordingly, improvements in structures and methods for fabricating the image sensor continue to be sought.